It was narrated that Abu Dharr said:

"We fasted with the Messenger of Allah ﷺ in Ramadan and he did not lead us in praying Qiyam until there were seven days left in the month, when he led us in praying Qiyam until one-third of the night had passed. Then he did not lead us in praying Qiyam when there were six days left. Then he led us praying Qiyam when there were five days left until one-half of the night had passed. I said: "O Messenger of Allah! What if we spend the rest of this night praying Nafl?" He said: "Whoever prays Qiyam with the Imam until he finishes, Allah (Subhanahu-wa-Taala) will record for him the Qiyam of a (whole) night." Then he did not lead us in prayer or pray Qiyam until there were three days of the month left. Then he led us in praying Qiyam when there were three days left. He gathered his family and wives (and led us in prayer) until we feared that we would miss Al-Falah. I (one of the narrators) said: "What is Al-Falah?" He said: "The suhur".

أَخْبَرَنَا عُبَيْدُ اللَّهِ بْنُ سَعِيدٍ، قَالَ حَدَّثَنَا مُحَمَّدُ بْنُ الْفُضَيْلِ، عَنْ دَاوُدَ بْنِ أَبِي هِنْدٍ، عَنِ الْوَلِيدِ بْنِ عَبْدِ الرَّحْمَنِ، عَنْ جُبَيْرِ بْنِ نُفَيْرٍ، عَنْ أَبِي ذَرٍّ، قَالَ صُمْنَا مَعَ رَسُولِ اللَّهِ ﷺ فِي رَمَضَانَ فَلَمْ يَقُمْ بِنَا حَتَّى بَقِيَ سَبْعٌ مِنَ الشَّهْرِ فَقَامَ بِنَا حَتَّى ذَهَبَ ثُلُثُ اللَّيْلِ ثُمَّ لَمْ يَقُمْ بِنَا فِي السَّادِسَةِ فَقَامَ بِنَا فِي الْخَامِسَةِ حَتَّى ذَهَبَ شَطْرُ اللَّيْلِ فَقُلْتُ يَا رَسُولَ اللَّهِ لَوْ نَفَّلْتَنَا بَقِيَّةَ لَيْلَتِنَا هَذِهِ . قَالَ " إِنَّهُ مَنْ قَامَ مَعَ الإِمَامِ حَتَّى يَنْصَرِفَ كَتَبَ اللَّهُ لَهُ قِيَامَ لَيْلَةٍ " . ثُمَّ لَمْ يُصَلِّ بِنَا وَلَمْ يَقُمْ حَتَّى بَقِيَ ثَلاَثٌ مِنَ الشَّهْرِ فَقَامَ بِنَا فِي الثَّالِثَةِ وَجَمَعَ أَهْلَهُ وَنِسَاءَهُ حَتَّى تَخَوَّفْنَا أَنْ يَفُوتَنَا الْفَلاَحُ . قُلْتُ وَمَا الْفَلاَحُ قَالَ السُّحُورُ .